This invention relates generally to the art of pipe networks for buildings and especially to apparatus and methods for embedding pipes in floors and walls and making fire-retardant pipe networks.
Until recently, pipe networks were normally extended through floors of buildings by formings holes in the floors --e.g. by using void-forming devices during the "pouring" of the concrete floors, by knocking out holes, by boring such holes after the floors had been formed, etc. --and thereafter extending pipes through these holes. Normally, the holes were made to be bigger than the pipes to ensure that one could easily extend the pipes through the holes. Thereafter, it was necessary for workmen to fill the spaces between the pipes and the floors with cement or some other substance to meet fire codes which generally do not allow holes in floors.
There have been a number of patents and other U.S. documents published such as German Offenlegungsshrift No. 2,615,428, U.S. Pat. No. 4,453,354 to Harbeke, and U.S. Pat. No. 4,261,598 to Cornwall disclosing the concept of cementing pipe coupling joints into floors when the floors are poured (sometimes called "cast-in couplings" ) and thereafter, mating external pipes to female opposite ends of the thusly embedded coupling joints. Such a practice is normally carried out with plastic pipes, however, it could also be carried out with pipes made of other materials. A difficulty with these specialized pipe-coupling joints is that they are relatively expensive, they are sometime difficult to cut to be proper lengths for various concrete-pour thicknesses, and most of them do not prevent the spread of fire from a lower story to a higher story. It is an object of this invention to provide a method and kit which allows one to construct a "cast-in" coupling from a pipe stub cut from normal, inexpensive, pipe to be a proper length for a desired concrete-pour thickness which retards the spread of fire between stories.
With regard to the "spread of fires", a major problem which still exists for plastic pipe-coupling joints which are embedded in floors is that when there is a fire, the fire melts external plastic pipes and then pass up through the embedded pipe-coupling joints themselves to the next higher floor. In other words, the embedded, or "cast-in" pipe coupling joints themselves serve as ventilation holes for fires. It has been suggested, and some fire codes require, that intumescent material surround plastic pipes where they pass through floor barriers. Upon being heated by a fire in the story below, the intumescent material will swell, thereby compressing the plastic pipe closed at the floor barrier and prevent the fire from spreading through the floor barrier. However, many of the embedded, "cast-in", coupling joints are thicker than regular pipe and many of them overlap pipes coupled from opposite ends along practically their entire lengths. Thus, intumescent material surrounding such embedded pipe joints would have to compress the thicker pipe coupling joint and in some cases would also have to compress the pipe itself before it could close off the pipe. It will be appreciated that compression through so much thickness of plastic is much more difficult than if the intumescent material were only compressing one normal pipe itself. Thus, it is an object of this invention to provide a kit and process for preparing an embedded pipe coupling joint which allows intumescent material to be placed about a normal, one-layer, pipe at a floor barrier.
In addition, many prior art embedded pipe coupling joints have flanges at their bottom ends which are used to attach the coupling joints to floor cement forms. Once the forms are removed these flanges serve as barriers to prevent heat from rising along the joints to contact intumescent material wrapped thereabout and thereby delay the heating of the intumescent material and its swelling. Thus, it is a further object of this invention to provide a kit and process for preparing an embedded pipe coupling joint from a stub cut from normal pipe which is surrounded by intumescent material which is open to atmosphere from the story below so that it can quickly receive heat therefrom.
It is a further object of this invention to provide a kit and process for making a fire-retardant fluid coupling which acts quickly enough to prevent a fire from spreading to the next higher story through a bore of the fluid coupling.
It is still another object of this invention to provide a kit and process for making such a fire-retardant fluid coupling which can be easily mounted on a concrete form wall for embedding the coupling in concrete.